Couplants - GE C-PT Installation Manual

4. Couplants

GE supplies an ultrasonic couplant for your C-PT installation. The purpose of the couplant is to provide reliable
transmission of ultrasound between two adjacent solid surfaces. Generally speaking, couplants perform this task by
excluding air from between the adjacent surfaces. Accordingly, the C-PT transducers should be pressed tightly against
the pipe, using hand pressure on the set screw to squeeze the couplant to as thin a film as practical for the given pipe
surface.
The most commonly used couplants in ultrasonic testing are ordinarily satisfactory for any short-term clamp-on
flowmeter application. These couplants include, in general order of preference: gels, grease, propylene glycol, oil,
glycerine, and water. Long-term couplants include grease, epoxy adhesive, and solid rubber-like sheet couplant.
GE provides couplants for both permanent and temporary use as well as for high- and low-temperature applications.
For long-term installations, make sure the couplant does not dry or run out.
Standard couplants supplied from GE are listed in Table 1.
Part No.
CPL-1
CPL-2 High/Low Temperature
CPL-3
CPL-4
CPL-7
CPL-8
* Installations involving hotter or colder temperatures than listed above, may require special
couplants. Consult GE for these applications.
C-PT Ultrasonic Flow Transducer Installation Guide
Table 1: Couplants
Type
Standard –40 to 149°F (–40 to 65°C)
–256 to 500°F (–160 to 260°C)
Portable –4 to 140°F (–20 to 60°C)
Special
Epoxy 14 to 122°F (–10 to 50°C)
Solid Sheet –40 to 446°F (–40 to 130°C)
Temp. Range
As Required
Use
Semi-Permanent
Semi-Permanent
Temporary
* Difficult Applications
Permanent
Permanent
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